A power supply often has an inverter or converter device for the conversion of available power from one set of characteristics to another set of characteristics for meeting specified requirements. A power supply can therefore be a circuit that provides from a mains supply power source an output power with the characteristics suitable for the load. For example, a mains supply power source might have the characteristics of 50 Hertz (Hz), single-phase, 240-Volt AC power found in Australia, whereas the load, such as electronics of a personal computer or a 20-Watt halogen light supply, might expect to receive regulated 5-Volt DC power, in which case a power supply includes a circuit for making the 240-Volt AC power source compatible with a 5-Volt DC load.
A switch-mode power supply is a type of power supply that provides power supply functionality by employing low-loss components such as capacitors, inductors, and transformers; and by the use of switches capable of two states—on or off. An advantage of such a system is that its switches dissipate very little power in either of the two states, and so power conversion can be accomplished at minimal power loss, thereby improving efficiency.
Electronic transformers for halogen lamps are typically designed for 20 Watts (or more) of resistive loads. The conventional inverters that are used expect the correct load so as to maintain oscillation—capacitances greater than 100 pF can stall the conventional inverter. Generally, inverters have over-current detection for detecting currents exceeding a predetermined maximum and, in response, initiating a temporary shutdown. There are two ways a transformer stalls, either incorrect phase shift (capacitive load), or over current.
Typical energy-saving products implement standard diode-based rectifiers including capacitance for stable operation and electromagnetic compliance (EMC). However, inrush currents can exceed 15 Amps when inverters first start, stalling oscillation and damaging rectifiers, causing early failure in both transformers and energy-saving globes.
It is an object of the present disclosure to describe an improved power supply control system and device that overcomes or at least ameliorates one or more of the disadvantages of the prior art.